1. Field of the Invention
The invention relates to a roll-up device for a safety belt for a motor vehicle with a mechanism for blocking the belt shaft in case of a crash. The belt shaft is provided with a locking pawl device that can be operated by a release mechanism, which can be coupled with the belt shaft supported in stable bearings of the basic frame of the roll-up device.
2.Description of the Prior Art
In known roll-up devices for safety belts of the above-mentioned type, (U.S. Pat. No. 3,901,459) a roll-up spring is arranged on one side of the belt shaft, while the opposite shaft end is connected with a locking pawl device and a release mechanism. In case of danger, i.e. at an acceleration or deceleration which exceeds a permissible limit, the release mechanism which, for example, is provided with inertial mass, acts upon a control disc and the control disc effects, through a locking pawl, the blocking of the belt shaft. The locking pawl and with it, locking teeth which are disposed in the same plane as the locking pawl, are arranged adjacent to the side plates of the U-shaped basic frame, while the load-bearings for the belt shaft are located in the stable side plates. For reasons of stability, the bearings which have a relatively large bearing diameter, have to be very accurately manufactured in order to avoid, during normal operation of the roll-up device for the safety belt i.e. when attaching or detaching the safety belt, high bearing friction and annoying bearing noises when the belt is rolled up. The manufacture of such load bearings is very costly and yet do not achieve desired advantages with respect to operation and low noise.